The present invention relates to an online line-scan imaging system capable of both hyperspectral and multispectral visible/near-infrared reflectance and to a method of using the system to inspect freshly slaughtered chickens on a processing line for wholesomeness and unwholesomeness. The system includes imaging apparatus, methods for image analysis and processing, and methods for use of this system for online inspection.
The Federal Meat Inspection Act of 1906 mandated postmortem inspection of meat and poultry carcasses and authorized the U.S. Department of Agriculture (USDA) to inspect slaughter and processing operations and sanitation for meat and poultry products intended for human consumption. The 1957 Poultry Product Inspection Act mandated postmortem inspection of every bird carcass processed by a commercial facility. Since then, USDA inspectors have conducted on-site organoleptic inspection of all chickens processed at U.S. poultry plants for indications of diseases or defects. Inspectors of the USDA Food Safety and Inspection Service (FSIS) examine by sight and by touch the body, the inner body cavity surfaces, and the internal organs of every chicken carcass during processing operations.
With the 1996 final rule on Pathogen Reduction and Hazard Analysis and Critical Control Point (HACCP) systems (USDA, Final Rule, Fed. Reg., Volume 61, 38805-38989, 1996), FSIS implemented the HACCP and Pathogen Reduction programs in meat and poultry processing plants throughout the country to prevent food safety hazards, to set specific food safety performance standards, and to establish testing programs to ensure that the performance standards are met, through the use of science-based process control systems. More recently, FSIS has also been testing the HACCP-Based Inspection Models Project (HIMP) in a small number of volunteer plants (USDA, Proposed Rule, Fed. Reg., 62: 31553-31562 (1997). HIMP requirements include zero tolerance for unwholesome chickens exhibiting symptoms of “septox”—a condition of either septicemia or toxemia. Wholesome chickens do not exhibit symptoms of “septox”.
Septicemia is caused by the presence of pathogenic microorganisms or their toxins in the bloodstream, and toxemia results from toxins produced by cells at a localized infection or from the growth of microorganisms. Septox birds are considered to be unwholesome and USDA inspectors remove these unwholesome birds from the processing lines during their bird-by-bird inspections, which can, by law, be conducted at a maximum speed of 35 birds per minute (bpm) for an individual inspector. The inspection process is subject to human variability, and the inspection speed restricts the maximum possible output for the processing plants while also making inspectors prone to fatigue and repetitive injury problems. This limit on production throughput, combined with increases in chicken consumption and demand over the past 2 decades, places additional pressure on both chicken production and safety inspection system. U.S. poultry plants now process over 8.8 billion broilers annually (USDA, Poultry Production and Value—2006 Summary (2007). During processing at a typical U.S. poultry plant, birds are first slaughtered on kill lines and then transferred to evisceration lines on which inspection stations are located. Commercial evisceration lines in the U.S. currently may be operated at speeds up to 140 bpm; however, such processing lines require up to four inspection stations, each with an FSIS inspector to conduct bird-by-bird inspection at the 35 bpm speed limit.
Machine vision technologies have been developed to address a variety of food and agricultural processing applications. Various sensing techniques such as RGB (red/green/blue) color imaging, visible and near-infrared (Vis/NIR) spectroscopy and imaging, fluorescence spectroscopy and imaging, and X-ray imaging, have been investigated for potential use in food processing and online inspection applications (Daley et al., Proc. SPIE, 2345: 403-411 (1994); Delwiche et al., Cereal Chem., 75: 412-416 (1998); Chao et al., Applied Engineering in Agriculture, 19(4): 453-458 (2003); Chao et al., Applied Engineering in Agriculture, 20(5): 683-690 (2004); Lu and Ariana, Applied Engineering in Agriculture, 18(5): 585-590 (2002); Lu, Trans. ASAE, 46(2): 523-530 (2003); Kim et al., Applied Optics, 42(9): 3927-3934 (2002); Mehl et al., Applied Engineering in Agriculture, 18(2): 219-226, 2002; Vargas et al., J. Food Science, 70(8): 471-476 (2003); Chen et al., Applied Optics, 40(8): 1195-2000 (2001).
A variety of methods for imaging whole chicken carcasses and chicken viscera/organs have been investigated for use in food safety inspection of poultry. RGB color imaging of chicken spleens, hearts, and livers was found capable of identifying poultry disease conditions including leucosis, septicemia, airsacculitis, and ascites in the laboratory (Tao et al., Proc. SPIE, 3544: 138-145 (1998); Chao et at, Applied Engineering in Agriculture, 15(4): 363-369 (1999), but these methods required precise presentation of the visceral organs and thus were unsuitable for conventional poultry processing lines. A two-camera system using two wavebands in the visible spectrum for whole-carcass imaging was able to separate 90% of wholesome and unwholesome chickens at processing line speeds up to 70 bpm, but was not feasible for higher speed processing (Park and Chen, J. Food Processing Engineering, 23(5): 329-351 (2000); Chao et al., J. Food Engineering, 51(3): 185-192 (2002).
Thus there remains a need to develop systems that can inspect chickens for wholesomeness in commercial processing lines which operate at speeds of at least 140 bpm.
We have found that with appropriate methods of hyperspectral analysis and algorithms for online image processing, a machine vision system utilizing an EMCCD (Electron-Multiplying Charge-Coupled-Device) camera for multispectral inspection can satisfy both the food safety performance standards and the high-speed production requirements (e.g., at least 140 bpm) of commercial chicken processing. A system of this type can perform food safety inspection tasks accurately and with less variation in performance at high speeds (e.g., at least 140 bpm), and help poultry plants to improve production efficiency and satisfy increasing consumer demand for poultry products.